Process for fermenting sugar-containing liquids with yeast



United States Patent Ofiice 3,022,225 Patented Feb. 20, 1962 3,022,225 PROCESS FOR FERMENTING SUGAR-CONTAIN- ING LIQUIDS WITH YEAST Pierre Colin, Melle, Deux-Sevres, France, assignor to Les Usines de Melle (Societe Anonyme), a corporation of France No Drawing. Filed June 17, 1960, Ser. No. 36,709

Claims priority, application France May 19, 1960 10 Claims. (Cl. 19537) This invention relates to fermenting sugar-containing liquids to produce ethyl alcohol.

The principal object of the invention is to provide a simple, efficient process of the kind described, which shall produce increased yields of ethyl alcohol.

The invention accordingly comprises the novel processes and steps of processes, specific embodiments of which are described hereinafter by way of example and in accordance with which I now prefer to practice the invention.

In carrying out the invention I ferment by means of yeast a sugar-containing liquid in the presence of a monohydric saturated aliphatic alcohol. The alcohol contains at least 6 carbon atoms and may consist of one such alcohol or a mixture of such alcohols. The alcohol is present during the fermentation process and is usually added at the commencement thereof. Aside from the presence of this alcohol the fermentation of the sugar is conducted in the usual manner, and is preferably conducted using the so-called yeast recovery process as set forth in US. Patent No. 2,054,736. The sugar-containing liquids employed are those commonly employed in fermentation of sugars to ethyl alcohol, more particularly liquids containing sucrose or similar disaccharide. In accordance with the invention there may be used straight-chain alcohols, such as n-hexanol or n-heptanol, or branched-chain alcohols, such as 2zethylbutanol or 2:ethylhexanol. A mixture of such alcohols which may be employed is a mixture of monohydric saturated aliphatic alcohols consisting mostly of C C C or of C alcohols produced by the x0 synthesis. This wellknown synthesis consists in reacting carbon monoxide and hydrogen with an olefine or olefine mixture, in the presence of a carbonyl-forming metal catalyst, thus producing carbonyl compounds having one more carbon atom than the starting olefine molecules, then the carbonly compounds are hydrogenated to the corresponding alcohol or alcohols.

The C- C C alcohols mixture and the C alcohols mixture mentioned above are produced by the 0x0 synthesis starting from an olefinic mixture containing C C and C olefines, or a mixture of C olefines, respectively.

Such alcohols mixtures are referred to in Table I below.

Another mixture which may economically be used and which contains alcohols of the kind described, besides other substances, is an alcoholic fraction recovered during distillation of the raw 2zethylhexanol produced by the conventional process of hydrogenating ethyl propyl acrolein. This fraction is liquid, water-soluble, distills above C. under an absolute pressure of 15 mm.

mercury, and has an average specific weight of 0.850.

It contains mainly decanols and minor proportions of dodecanols and higher alcohols. It is referred to in Example 2 below as alcohol fraction containing decanols, dodecanols and higher alcohols.

It has been found that the above-described alcohols and mixtures containing such alcohols are highly favorable adjuvants or assistants for alcoholic fermentation of sugar-containing liquids. The proportion to be employed of said assistants is generally low. Such assistants amazingly produce an increase in the fermentation yield (that is, the amount of alcohol produced per parts of sugar put into operation), which increase generally varies from 1.5% to 5% according to the fermentation medium (for example, sugar-beet musts seem to provide the greatest increases), or the fermentation conditions.

In accordance with the present invention the alcohols employed as fermentation assistants are used preferably in proportion of 0.1-0.5 part by volume per one thousand parts by volume of sugar-containing liquid undergoing fermentation. For example, for sugar-beet musts the optimum proportions are 0.1-0.5 per one thousand, but a proportion as high as 1.5 parts by volume per one thousand does not impede the fermentation work. For mollasses-musts, the optimum proportions are 0.1-0.15 per one thousand. Generally, it is preferred that the alcohol or alcoholic mixture constituting the assistant be introduced into the fermentation apparatus together with the sugar-containing liquid to be fermented.

The following examples are illustrative of the manner in which I now prefer to carry out the invention. These examples are illustrative, as stated, and the invention is not to be considered as restricted thereto except as indicated in the appended claims.

EXAMPLE 1 There were performed two parallel, laboratory-scale sets of alcoholic fermentation operations using a sugarbeet must, one of the operations being a blank one, carried out Without addition of an alcoholic assistant, while the other was performed in the presence of an alcoholic assistant in accordance with the invention. The quantities of ingredients are specified in the table below:

Table 1 Sugar Liquid Yeast Alcohol Yield Increase, percent Proportion of Additive Used (parts by volume per 1,000 Kg. parts of Must) Ethyl Ethyl Alcohol Yield, percent of sugar Additive 0.75 litres sugar-beet must."

0.008 kilos containing 75% water.

None

None.

9 99. 9. 9 ow tnHUIOlUvOJ of a primary alky-l alcohol containing 6 to 12 carbon atoms.

3. A process in; accordance with claim 2, in which said primary alkyl alcohol is n-hexanol.

4. A process in accordance with claim 2, in which said primary alkyl alcohol is n-heptanol.

5. A process in accordance with claim 2, in which said primary alkyl alcohol is 2zethylbutanol.

' 6. A process in accordance with claim 2, in which said primary alkyl alcohol is 2gethylhexanol. p 7. A procms for producing ethyl alcohol, which comprises fermenting a disaccharide-containing liquid with Table I1 Proportion of Ethyl Ethyl Alcohol Additive Used Alcohol Alcohol Yield Sugar-Liquid (per day) Yeast Additive (parts by vol- Yield, Yield, Increase, urne per 1,000 Kg. per percent percent parts of Must) day of sugar 1,000,000 litressugar-beet must. 80,000 kilos Nrme None 55,360 49.9

7 containing 7 85% water. Do do.. 2-ethylhexanol 0. 4 56,960 51.4 3 Do dn Alcohol fraction containing 0.5 56, 430 50.9 2

" decanols, dodecanols and higher alcohols prepared as above stated. 1,000 litres Molasses Must 100 kilos con- None None 68.0 50.4

' taining 87% 7 water. I Do. do The same alcohol fraction as 0. 1 69. 1 51. 2 1. 6 7 above. 4

Ethyl alcohol obtained in accordance withthe two examples above,-is separated in the usual manner by distillation from the fermented mass.

The foregoing examples illustrate the use of beet-musts and of molasses-musts, which are most often employed in industry, but it is within the scope of the present in-. vention to use other kinds of musts containing fermentable sugars.

I claim: 7

1. A process for producing ethyl alcohol, which comprises fermenting a sugar-containing liquid with yeast 'in the presence of about 0.1 to 1.5 volumes per one thousand volumes of said sugar-containing liquid of a primary alkyl alcohol containing 6 to 12 carbon atoms. 7

2. A process for producing ethyl alcohol, which comprises fermenting a disaccharide-containing liquid with yeast in the presence of about 0.1 to 1.5 volumes per one thousand volumes of said disaccharide-containing liquid yeast in the presence of about 0.1 to 1.5 volumes per one thousand volumes of said disaccharide-containing liquid of a mixture of primary alkyl alcohols containing decanols and dodecanols. f I 8. A process for producing ethyl alcohol, which. comprises fermenting a disaccharide-containing' liquidwith yeast in the presence of about 0.1 to 1.5 volumes per one thousand volumes of said disaccharide-containing liquid of a mixture of C -C C and .0 primary alkyl alcohols.

9. A process as set forth in claim 2 wherein the disaccharide-containing liquid is a sugar beet must. i

10. A process as set forth in claim 2 wherein the disaccharide-containing liquid is a molasses must. 4

References Cited in the fileof this patent UNITED STATES PATENTS 

1. A PROCESS FOR PRODUCING ETHYL ALCOHOL, WHICH COMPRISES FERMENTING A SUGAR-CONTAINING LIQUID WITH YEAST IN THE PRESENCE OF ABOUT 0.1 TO 1.5 VOLUMES PER ONE THOUSAND VOLUMES OF SAID SUGAR-CONTAINING LIQUID OF A PRIMARY ALKYL ALCOHOL CONTAINING 6 TO 12 CARBON ATOMS. 